Product manual

The offset boundary field returns the boundary alignment
within the selected buffer for subsequent WRITE BUFFER
and READ BUFFER commands. The value contained in the
offset boundary field shall be interpreted as a power of two.
Buffer Offset Boundary
Offset Boundary 20 Offset Boundary Buffer Offsets
52
5
= 32 32-byte boundaries
FF
H
Not Applicable
0 is the only
supported buffer
offset
The buffer capacity field returns the size of the selected
buffer in bytes.
All other settings for the
mode bits are reserved.
Byte 2
The
buffer ID is not supported and must always be zero.
Byte 3–5
The
buffer offset is added to the starting address of the
buffer to determine the source of the first data byte. The
bytes that follow are read from sequential addresses. If the
sum of the buffer offset and the transfer length exceeds the
available length reported in the Read Buffer header (see
Section 3.6.9.1), the drive transfers all the data contained
in the buffer.
Bytes 6–8
The
allocation length field specifies the maximum number
of bytes read by the initiator. If the 4-byte header is trans-
ferred, the transfer length includes the header. If the transfer
length is zero, no data is read;
this is not an error.
3.6.9.1 Read Buffer Header
The following table shows the structure of the 4-byte Read Buffer Header.
Bytes
Bits
76543210
00
1–3 Buffer capacity
Bytes 1–3
The
buffer capacity field specifies the size of the drive
buffer. Byte 1 is MSB; byte 3 is LSB.
Medalist Pro 2160N/2160WC Product Manual, Rev. A 73